diff --git a/include/reign.h b/include/reign.h
index f6c4888..b5424dc 100644
--- a/include/reign.h
+++ b/include/reign.h
@@ -165,6 +165,8 @@ struct RE_instance {
 	mat4 local_transform;
 	mat3 normal_transform;
 	mat4 *bone_transforms;  // model->nr_bones elements
+	vec4 bounding_sphere;
+	struct RE_instance *shadow_volume_instance;
 	float z_from_camera;
 };
 
@@ -186,6 +188,7 @@ bool RE_instance_set_vertex_pos(struct RE_instance *instance, int index, float x
 int RE_instance_get_bone_index(struct RE_instance *instance, const char *name);
 bool RE_instance_trans_local_pos_to_world_pos_by_bone(struct RE_instance *instance, int bone, vec3 offset, vec3 out);
 float RE_instance_calc_height(struct RE_instance *instance, float x, float z);
+bool RE_instance_set_debug_draw_shadow_volume(struct RE_instance *instance, bool draw);
 
 int RE_motion_get_state(struct motion *motion);
 bool RE_motion_set_state(struct motion *motion, int state);
diff --git a/shaders/reign.f.glsl b/shaders/reign.f.glsl
index 6517383..fd29a6b 100644
--- a/shaders/reign.f.glsl
+++ b/shaders/reign.f.glsl
@@ -52,7 +52,7 @@ uniform bool use_specular_map;
 uniform float rim_exponent;
 uniform vec3 rim_color;
 uniform int diffuse_type;
-uniform bool use_shadow_map;
+uniform float shadow_darkness;
 uniform float shadow_bias;
 uniform int fog_type;
 uniform float fog_near;
@@ -133,26 +133,26 @@ void main() {
 	}
 
 	// Shadow mapping
-	if (use_shadow_map) {
+	if (shadow_darkness > 0.0) {
 		vec3 shadow_coords = shadow_frag_pos.xyz / shadow_frag_pos.w * 0.5 + 0.5;
 		shadow_coords.z = min(1.0, shadow_coords.z - shadow_bias);
 		// PCF with 9 samples.
-		float shadow_factor = 1.0;
+		float brightness = 1.0;
 		vec2 texel_size = 1.0 / vec2(textureSize(shadow_texture, 0));
 		for (int x = -1; x <= 1; ++x) {
 			for (int y = -1; y <= 1; ++y) {
 				float depth = texture(shadow_texture, shadow_coords.xy + vec2(x, y) * texel_size).r;
 				if (depth < shadow_coords.z)
-					shadow_factor -= 0.05;
+					brightness -= 0.05 * shadow_darkness;
 			}
 		}
-		frag_rgb *= shadow_factor;
+		frag_rgb *= brightness;
 	}
 
 	// Alpha mapping
 	float alpha = texel.a * alpha_mod;
 	if (alpha_mode == ALPHA_TEST) {
-		if (alpha < 1.0)
+		if (alpha < 0.8)
 			discard;
 	} else if (alpha_mode == ALPHA_MAP_BLEND) {
 		alpha *= texture(alpha_texture, tex_coord).r;
diff --git a/src/3d/3d_internal.h b/src/3d/3d_internal.h
index 3ef56e1..ff078f0 100644
--- a/src/3d/3d_internal.h
+++ b/src/3d/3d_internal.h
@@ -51,7 +51,9 @@ struct mesh {
 	uint32_t flags;
 	GLuint vao;
 	GLuint attr_buffer;
+	GLuint index_buffer;
 	int nr_vertices;
+	int nr_indices;
 	int material;
 };
 
@@ -65,6 +67,7 @@ struct material {
 	GLuint normal_map;
 	float specular_strength;
 	float specular_shininess;
+	float shadow_darkness;
 	float rim_exponent;
 	vec3 rim_color;
 };
@@ -143,7 +146,7 @@ struct RE_renderer {
 	GLint light_texture;
 	GLint use_normal_map;
 	GLint normal_texture;
-	GLint use_shadow_map;
+	GLint shadow_darkness;
 	GLint shadow_transform;
 	GLint shadow_texture;
 	GLint shadow_bias;
@@ -176,6 +179,7 @@ void RE_instance_update_local_transform(struct RE_instance *inst);
 
 struct model *model_load(struct archive *aar, const char *path);
 void model_free(struct model *model);
+struct model *model_create_sphere(int r, int g, int b, int a);
 
 struct motion *motion_load(const char *name, struct RE_instance *instance, struct archive *aar);
 void motion_free(struct motion *motion);
@@ -393,6 +397,7 @@ enum mesh_flags {
 	MESH_NOMAKESHADOW = 1 << 1,
 	MESH_ENVMAP       = 1 << 2,
 	MESH_BOTH         = 1 << 3,
+	MESH_SPRITE       = 1 << 4,
 };
 
 struct pol_mesh {
@@ -425,7 +430,7 @@ struct pol_triangle {
 	uint32_t uv_index[3];
 	uint32_t light_uv_index[3];
 	vec3 normals[3];
-	uint32_t material;  // index in the material group
+	uint32_t material_group_index;
 };
 
 struct pol_bone {
@@ -468,6 +473,8 @@ struct amt_material {
 enum amt_field_index {
 	AMT_SPECULAR_STRENGTH = 0,
 	AMT_SPECULAR_SHININESS = 2,
+	// amt v4+
+	AMT_SHADOW_DARKNESS = 6,
 	// amt v5+
 	AMT_RIM_EXPONENT = 7,
 	AMT_RIM_R = 8,
diff --git a/src/3d/model.c b/src/3d/model.c
index 15ac432..3936284 100644
--- a/src/3d/model.c
+++ b/src/3d/model.c
@@ -110,12 +110,15 @@ static bool init_material(struct material *material, const struct pol_material *
 	if (m->textures[NORMAL_MAP])
 		material->normal_map = load_texture(aar, path, m->textures[NORMAL_MAP], NULL);
 
-	material->is_transparent = has_alpha || material->alpha_map;
+	material->is_transparent = (has_alpha || material->alpha_map) && !(material->flags & MATERIAL_SPRITE);
+	material->shadow_darkness = 1.0f;
 
 	struct amt_material *amt_m = amt ? amt_find_material(amt, m->name) : NULL;
 	if (amt_m) {
 		material->specular_strength = amt_m->fields[AMT_SPECULAR_STRENGTH];
 		material->specular_shininess = amt_m->fields[AMT_SPECULAR_SHININESS];
+		if (amt->version >= 4)
+			material->shadow_darkness = amt_m->fields[AMT_SHADOW_DARKNESS];
 		if (amt->version >= 5) {
 			material->rim_exponent = amt_m->fields[AMT_RIM_EXPONENT];
 			material->rim_color[0] = amt_m->fields[AMT_RIM_R];
@@ -211,7 +214,7 @@ static void *buf_alloc(uint8_t **ptr, int size)
 	return p;
 }
 
-static void add_mesh(struct model *model, struct pol_mesh *m, int material_index, int material)
+static void add_mesh(struct model *model, struct pol_mesh *m, uint32_t material_group_index, int material)
 {
 	bool has_light_map = m->light_uvs && model->materials[material].light_map;
 	bool has_normal_map = model->materials[material].normal_map != 0;
@@ -231,7 +234,7 @@ static void add_mesh(struct model *model, struct pol_mesh *m, int material_index
 	int nr_vertices = 0;
 	for (uint32_t i = 0; i < m->nr_triangles; i++) {
 		struct pol_triangle *t = &m->triangles[i];
-		if (material_index >= 0 && t->material != (uint32_t)material_index)
+		if (t->material_group_index != material_group_index)
 			continue;
 		vec4 tangent[3];
 		if (has_normal_map)
@@ -336,6 +339,8 @@ static void destroy_mesh(struct mesh *mesh)
 {
 	glDeleteVertexArrays(1, &mesh->vao);
 	glDeleteBuffers(1, &mesh->attr_buffer);
+	if (mesh->index_buffer)
+		glDeleteBuffers(1, &mesh->index_buffer);
 }
 
 static struct bone *add_bone(struct model *model, struct pol *pol, struct pol_bone *pol_bone)
@@ -460,7 +465,7 @@ struct model *model_load(struct archive *aar, const char *path)
 		struct pol_material_group *mg = &pol->materials[pol->meshes[i]->material];
 		int m_off = material_offsets[pol->meshes[i]->material];
 		if (mg->nr_children == 0) {
-			add_mesh(model, pol->meshes[i], -1, m_off);
+			add_mesh(model, pol->meshes[i], 0, m_off);
 			continue;
 		}
 		for (uint32_t j = 0; j < mg->nr_children; j++) {
@@ -499,6 +504,101 @@ void model_free(struct model *model)
 	free(model);
 }
 
+static void init_sphere_mesh(struct mesh *mesh)
+{
+	const int w_segments = 16;
+	const int h_segments = 16;
+	const int nr_vertices = (w_segments + 1) * (h_segments + 1);
+	struct vertex_common *vertices = xcalloc(nr_vertices, sizeof(struct vertex_common));
+	struct vertex_common *v = vertices;
+	for (int y = 0; y <= h_segments; y++) {
+		float theta = GLM_PIf * y / h_segments;
+		for (int x = 0; x <= w_segments; x++, v++) {
+			float phi = 2.0f * GLM_PIf * x / w_segments;
+			v->pos[0] = -cosf(phi) * sinf(theta);
+			v->pos[1] = cosf(theta);
+			v->pos[2] = sinf(phi) * sinf(theta);
+			glm_vec3_copy(v->pos, v->normal);
+			v->uv[0] = v->uv[1] = 0.0f;
+		}
+	}
+	assert(v == vertices + nr_vertices);
+
+	const int nr_indices = 3 * 2 * w_segments * (h_segments - 1);
+	GLushort *indices = xcalloc(nr_indices, sizeof(GLushort));
+	GLushort *pi = indices;
+	for (int y = 0; y < h_segments; y++) {
+		for (int x = 0; x < w_segments; x++) {
+			GLushort a = y * w_segments + x + 1;
+			GLushort b = y * w_segments + x;
+			GLushort c = (y + 1) * w_segments + x;
+			GLushort d = (y + 1) * w_segments + x + 1;
+			if (y > 0) {
+				*pi++ = a;
+				*pi++ = b;
+				*pi++ = d;
+			}
+			if (y < h_segments - 1) {
+				*pi++ = b;
+				*pi++ = c;
+				*pi++ = d;
+			}
+		}
+	}
+	assert(pi == indices + nr_indices);
+
+	mesh->flags = MESH_NOLIGHTING;
+	mesh->nr_vertices = nr_vertices;
+	mesh->nr_indices = nr_indices;
+	glGenVertexArrays(1, &mesh->vao);
+	glBindVertexArray(mesh->vao);
+	glGenBuffers(1, &mesh->attr_buffer);
+	glBindBuffer(GL_ARRAY_BUFFER, mesh->attr_buffer);
+	glBufferData(GL_ARRAY_BUFFER, nr_vertices * sizeof(struct vertex_common), vertices, GL_STATIC_DRAW);
+	glEnableVertexAttribArray(VATTR_POS);
+	glVertexAttribPointer(VATTR_POS, 3, GL_FLOAT, GL_FALSE, sizeof(struct vertex_common), (void*)offsetof(struct vertex_common, pos));
+	glEnableVertexAttribArray(VATTR_NORMAL);
+	glVertexAttribPointer(VATTR_NORMAL, 3, GL_FLOAT, GL_FALSE, sizeof(struct vertex_common), (void*)offsetof(struct vertex_common, normal));
+	glEnableVertexAttribArray(VATTR_UV);
+	glVertexAttribPointer(VATTR_UV, 2, GL_FLOAT, GL_FALSE, sizeof(struct vertex_common), (void*)offsetof(struct vertex_common, uv));
+
+	glGenBuffers(1, &mesh->index_buffer);
+	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mesh->index_buffer);
+	glBufferData(GL_ELEMENT_ARRAY_BUFFER, nr_indices * sizeof(GLushort), indices, GL_STATIC_DRAW);
+	glBindVertexArray(0);
+
+	free(vertices);
+	free(indices);
+}
+
+struct model *model_create_sphere(int r, int g, int b, int a)
+{
+	struct model *model = xcalloc(1, sizeof(struct model));
+
+	model->nr_meshes = 1;
+	model->meshes = xcalloc(1, sizeof(struct mesh));
+	init_sphere_mesh(&model->meshes[0]);
+	model->aabb[0][0] = -1.0f;
+	model->aabb[0][1] = -1.0f;
+	model->aabb[0][2] = -1.0f;
+	model->aabb[1][0] = 1.0f;
+	model->aabb[1][1] = 1.0f;
+	model->aabb[1][2] = 1.0f;
+
+	model->nr_materials = 1;
+	model->materials = xcalloc(1, sizeof(struct material));
+	struct material *material = &model->materials[0];
+	material->is_transparent = true;
+	glGenTextures(1, &material->color_map);
+	glBindTexture(GL_TEXTURE_2D, material->color_map);
+	uint8_t pixel[4] = {r, g, b, a};
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixel);
+	glBindTexture(GL_TEXTURE_2D, 0);
+	model->has_transparent_material = true;
+
+	return model;
+}
+
 static int cmp_motions_by_bone_id(const void *lhs, const void *rhs)
 {
 	return (*(struct mot_bone **)lhs)->id - (*(struct mot_bone **)rhs)->id;
diff --git a/src/3d/parser.c b/src/3d/parser.c
index 38d975a..228853f 100644
--- a/src/3d/parser.c
+++ b/src/3d/parser.c
@@ -134,7 +134,7 @@ static void destroy_vertex(struct pol_vertex *v)
 		free(v->weights);
 }
 
-static void parse_triangle(struct buffer *r, struct pol_mesh *mesh, int triangle_index, int unknowns_length)
+static void parse_triangle(struct buffer *r, struct pol_mesh *mesh, int triangle_index, int unknowns_length, const struct pol_material_group *mg)
 {
 	struct pol_triangle *t = &mesh->triangles[triangle_index];
 	t->vert_index[0] = buffer_read_int32(r);
@@ -154,7 +154,9 @@ static void parse_triangle(struct buffer *r, struct pol_mesh *mesh, int triangle
 	read_direction(r, t->normals[0]);
 	read_direction(r, t->normals[1]);
 	read_direction(r, t->normals[2]);
-	t->material = buffer_read_int32(r);
+	t->material_group_index = buffer_read_int32(r);
+	if (t->material_group_index >= mg->nr_children)
+		t->material_group_index = 0;
 }
 
 static uint32_t parse_mesh_attributes(const char *name)
@@ -168,10 +170,12 @@ static uint32_t parse_mesh_attributes(const char *name)
 		flags |= MESH_ENVMAP;
 	if (strstr(name, "(both)"))
 		flags |= MESH_BOTH;
+	if (strstr(name, "(sprite)"))
+		flags |= MESH_SPRITE;
 	return flags;
 }
 
-static struct pol_mesh *parse_mesh(struct buffer *r, int pol_version)
+static struct pol_mesh *parse_mesh(struct buffer *r, const struct pol *pol)
 {
 	int type = buffer_read_int32(r);
 	if (type != 0) {
@@ -183,11 +187,15 @@ static struct pol_mesh *parse_mesh(struct buffer *r, int pol_version)
 	mesh->name = read_cstring(r);
 	mesh->flags = parse_mesh_attributes(mesh->name);
 	mesh->material = buffer_read_int32(r);
+	if (mesh->material >= pol->nr_materials) {
+		WARNING("material index out of range (%d >= %d)", mesh->material, pol->nr_materials);
+		mesh->material = 0;
+	}
 
 	mesh->nr_vertices = buffer_read_int32(r);
 	mesh->vertices = xcalloc(mesh->nr_vertices, sizeof(struct pol_vertex));
 	for (uint32_t i = 0; i < mesh->nr_vertices; i++) {
-		parse_vertex(r, pol_version, &mesh->vertices[i]);
+		parse_vertex(r, pol->version, &mesh->vertices[i]);
 	}
 
 	mesh->nr_uvs = buffer_read_int32(r);
@@ -207,7 +215,7 @@ static struct pol_mesh *parse_mesh(struct buffer *r, int pol_version)
 	}
 
 	int triangle_unknowns_length = 12;
-	if (pol_version == 1) {
+	if (pol->version == 1) {
 		int nr_unknown_vecs = buffer_read_int32(r);
 		buffer_skip(r, nr_unknown_vecs * 12);
 	} else {
@@ -223,10 +231,10 @@ static struct pol_mesh *parse_mesh(struct buffer *r, int pol_version)
 	mesh->nr_triangles = buffer_read_int32(r);
 	mesh->triangles = xcalloc(mesh->nr_triangles, sizeof(struct pol_triangle));
 	for (uint32_t i = 0; i < mesh->nr_triangles; i++) {
-		parse_triangle(r, mesh, i, triangle_unknowns_length);
+		parse_triangle(r, mesh, i, triangle_unknowns_length, &pol->materials[mesh->material]);
 	}
 
-	if (pol_version == 1) {
+	if (pol->version == 1) {
 		if (buffer_read_int32(r) != 1)
 			WARNING("unexpected mesh footer");
 		if (buffer_read_int32(r) != 0)
@@ -288,7 +296,7 @@ struct pol *pol_parse(uint8_t *data, size_t size)
 	pol->nr_meshes = buffer_read_int32(&r);
 	pol->meshes = xcalloc(pol->nr_meshes, sizeof(struct pol_mesh *));
 	for (uint32_t i = 0; i < pol->nr_meshes; i++) {
-		pol->meshes[i] = parse_mesh(&r, pol->version);
+		pol->meshes[i] = parse_mesh(&r, pol);
 	}
 
 	pol->nr_bones = buffer_read_int32(&r);
diff --git a/src/3d/reign.c b/src/3d/reign.c
index d432488..a1e546f 100644
--- a/src/3d/reign.c
+++ b/src/3d/reign.c
@@ -39,19 +39,22 @@ static struct RE_instance *create_instance(struct RE_plugin *plugin)
 	instance->plugin = plugin;
 	for (int i = 0; i < RE_NR_INSTANCE_TARGETS; i++)
 		instance->target[i] = -1;
-	instance->scale[0] = 1.0;
-	instance->scale[1] = 1.0;
-	instance->scale[2] = 1.0;
-	instance->alpha = 1.0;
+	instance->scale[0] = 1.0f;
+	instance->scale[1] = 1.0f;
+	instance->scale[2] = 1.0f;
+	instance->alpha = 1.0f;
+	instance->shadow_volume_bone_radius = 0.1f;
 	instance->draw_bump = true;
-	instance->fps = 30.0;
-	instance->column_height = 1.0;
-	instance->column_radius = 1.0;
+	instance->fps = 30.0f;
+	instance->column_height = 1.0f;
+	instance->column_radius = 1.0f;
 	glm_mat4_identity(instance->local_transform);
 	glm_mat3_identity(instance->normal_transform);
 	return instance;
 }
 
+static void free_instance(struct RE_instance *instance);
+
 static void unload_instance(struct RE_instance *instance)
 {
 	if (instance->motion) {
@@ -78,6 +81,10 @@ static void unload_instance(struct RE_instance *instance)
 		RE_renderer_free_height_detector(instance->height_detector);
 		instance->height_detector = NULL;
 	}
+	if (instance->shadow_volume_instance) {
+		free_instance(instance->shadow_volume_instance);
+		instance->shadow_volume_instance = NULL;
+	}
 }
 
 static void free_instance(struct RE_instance *instance)
@@ -143,6 +150,10 @@ static void update_bones(struct RE_instance *inst)
 		return;
 
 	mat4 parent_transforms[MAX_BONES];
+	vec3 aabb[2];
+	glm_aabb_invalidate(aabb);
+
+	// Update inst->bone_transforms.
 	for (int i = 0; i < inst->model->nr_bones; i++) {
 		struct mot_frame mf;
 		calc_motion_frame(inst->motion, i, &mf);
@@ -162,6 +173,24 @@ static void update_bones(struct RE_instance *inst)
 		glm_mat4_copy(bone_transform, parent_transforms[i]);
 
 		glm_mat4_mul(bone_transform, inst->model->bones[i].inverse_bind_matrix, inst->bone_transforms[i]);
+
+		glm_vec3_minv(aabb[0], bone_transform[3], aabb[0]);
+		glm_vec3_maxv(aabb[1], bone_transform[3], aabb[1]);
+	}
+
+	// Update inst->bounding_sphere.
+	vec3 center;
+	glm_aabb_center(aabb, center);
+	if (inst->local_transform_needs_update)
+		RE_instance_update_local_transform(inst);
+	glm_mat4_mulv3(inst->local_transform, center, 1.0f, inst->bounding_sphere);
+	inst->bounding_sphere[3] = glm_aabb_radius(aabb) * inst->scale[0] + inst->shadow_volume_bone_radius;
+
+	struct RE_instance *shvol = inst->shadow_volume_instance;
+	if (shvol) {
+		glm_vec3_copy(inst->bounding_sphere, shvol->pos);
+		glm_vec3_broadcast(inst->bounding_sphere[3], shvol->scale);
+		RE_instance_update_local_transform(shvol);
 	}
 }
 
@@ -443,6 +472,19 @@ float RE_instance_calc_height(struct RE_instance *instance, float x, float z)
 	return y;
 }
 
+bool RE_instance_set_debug_draw_shadow_volume(struct RE_instance *inst, bool draw)
+{
+	if (!inst)
+		return false;
+	if (draw && !inst->shadow_volume_instance) {
+		inst->shadow_volume_instance = create_instance(inst->plugin);
+		inst->shadow_volume_instance->model = model_create_sphere(255, 0, 0, 64);
+	}
+	if (inst->shadow_volume_instance)
+		inst->shadow_volume_instance->draw = draw;
+	return true;
+}
+
 void RE_instance_update_local_transform(struct RE_instance *inst)
 {
 	vec3 euler = {
diff --git a/src/3d/renderer.c b/src/3d/renderer.c
index 7fcfd9c..ef8974e 100644
--- a/src/3d/renderer.c
+++ b/src/3d/renderer.c
@@ -27,8 +27,8 @@
 #include "sact.h"
 
 // TODO: Respect RE_plugin.shadow_map_resolution_level
-#define SHADOW_WIDTH 1024
-#define SHADOW_HEIGHT 1024
+#define SHADOW_WIDTH 512
+#define SHADOW_HEIGHT 512
 
 enum {
 	COLOR_TEXTURE_UNIT,
@@ -201,7 +201,7 @@ struct RE_renderer *RE_renderer_new(struct texture *texture)
 	r->light_texture = glGetUniformLocation(r->program, "light_texture");
 	r->use_normal_map = glGetUniformLocation(r->program, "use_normal_map");
 	r->normal_texture = glGetUniformLocation(r->program, "normal_texture");
-	r->use_shadow_map = glGetUniformLocation(r->program, "use_shadow_map");
+	r->shadow_darkness = glGetUniformLocation(r->program, "shadow_darkness");
 	r->shadow_transform = glGetUniformLocation(r->program, "shadow_transform");
 	r->shadow_texture = glGetUniformLocation(r->program, "shadow_texture");
 	r->shadow_bias = glGetUniformLocation(r->program, "shadow_bias");
@@ -317,7 +317,7 @@ static void render_model(struct RE_instance *inst, struct RE_renderer *r, enum d
 	for (int i = 0; i < model->nr_meshes; i++) {
 		struct mesh *mesh = &model->meshes[i];
 		struct material *material = &model->materials[mesh->material];
-		bool is_transparent = material->is_transparent || inst->alpha < 1.0f;
+		bool is_transparent = (material->is_transparent && !(mesh->flags & MESH_SPRITE)) || inst->alpha < 1.0f;
 		if (phase != (is_transparent ? DRAW_TRANSPARENT : DRAW_OPAQUE))
 			continue;
 
@@ -347,7 +347,10 @@ static void render_model(struct RE_instance *inst, struct RE_renderer *r, enum d
 		glBindTexture(GL_TEXTURE_2D, material->color_map);
 		glUniform1i(r->texture, COLOR_TEXTURE_UNIT);
 
-		glUniform1i(r->use_shadow_map, draw_shadow && !(mesh->flags & MESH_BOTH));
+		if (draw_shadow && !(mesh->flags & MESH_BOTH))
+			glUniform1f(r->shadow_darkness, material->shadow_darkness);
+		else
+			glUniform1f(r->shadow_darkness, 0.0f);
 
 		if (mesh->flags & MESH_ENVMAP) {
 			glUniform1i(r->diffuse_type, DIFFUSE_ENV_MAP);
@@ -376,14 +379,19 @@ static void render_model(struct RE_instance *inst, struct RE_renderer *r, enum d
 			glActiveTexture(GL_TEXTURE0 + ALPHA_TEXTURE_UNIT);
 			glBindTexture(GL_TEXTURE_2D, material->alpha_map);
 			glUniform1i(r->alpha_texture, ALPHA_TEXTURE_UNIT);
-		} else if (material->flags & MATERIAL_SPRITE) {
+		} else if (material->flags & MATERIAL_SPRITE || mesh->flags & MESH_SPRITE) {
 			glUniform1i(r->alpha_mode, ALPHA_TEST);
 		} else {
 			glUniform1i(r->alpha_mode, ALPHA_BLEND);
 		}
 
 		glBindVertexArray(mesh->vao);
-		glDrawArrays(GL_TRIANGLES, 0, mesh->nr_vertices);
+
+		if (mesh->nr_indices)
+			glDrawElements(GL_TRIANGLES, mesh->nr_indices, GL_UNSIGNED_SHORT, NULL);
+		else
+			glDrawArrays(GL_TRIANGLES, 0, mesh->nr_vertices);
+
 		glBindVertexArray(0);
 		glBindTexture(GL_TEXTURE_2D, 0);
 	}
@@ -405,13 +413,16 @@ static void render_skinned_model(struct RE_instance *inst, struct RE_renderer *r
 	if (!model)
 		return;
 
-	if (model->nr_bones > 0) {
+	if (model->nr_bones > 0 && inst->motion) {
 		glUniform1i(r->has_bones, GL_TRUE);
 		glUniformMatrix4fv(r->bone_matrices, model->nr_bones, GL_FALSE, inst->bone_transforms[0][0]);
 	} else {
 		glUniform1i(r->has_bones, GL_FALSE);
 	}
 	render_model(inst, r, phase);
+
+	if (inst->shadow_volume_instance && phase == DRAW_TRANSPARENT)
+		render_static_model(inst->shadow_volume_instance, r, phase);
 }
 
 static void render_billboard(struct RE_instance *inst, struct RE_renderer *r, mat4 view_mat, enum draw_phase phase)
@@ -452,7 +463,7 @@ static void render_billboard(struct RE_instance *inst, struct RE_renderer *r, ma
 	glUniform1f(r->rim_exponent, 0.0);
 	glUniform1i(r->diffuse_type, DIFFUSE_NORMAL);
 	glUniform1i(r->use_normal_map, GL_FALSE);
-	glUniform1i(r->use_shadow_map, GL_FALSE);
+	glUniform1f(r->shadow_darkness, 0.0f);
 	glUniform1i(r->alpha_mode, ALPHA_BLEND);
 	glUniform1i(r->fog_type, inst->plugin->fog_mode ? inst->plugin->fog_type : 0);
 	switch (inst->draw_type) {
@@ -572,7 +583,7 @@ static void render_particle_effect(struct RE_instance *inst, struct RE_renderer
 	glUniform1i(r->use_specular_map, GL_FALSE);
 	glUniform1f(r->rim_exponent, 0.0);
 	glUniform1i(r->use_normal_map, GL_FALSE);
-	glUniform1i(r->use_shadow_map, GL_FALSE);
+	glUniform1f(r->shadow_darkness, 0.0f);
 	glUniform1i(r->alpha_mode, ALPHA_BLEND);
 
 	glDepthMask(GL_FALSE);
@@ -626,52 +637,27 @@ static void render_instance(struct RE_instance *inst, struct RE_renderer *r, mat
 
 static bool calc_shadow_light_transform(struct RE_plugin *plugin, mat4 dest)
 {
-	// Compute AABB of shadow casters.
-	vec3 aabb[2];
-	glm_aabb_invalidate(aabb);
+	// Compute a bounding sphere of shadow casters.
+	vec4 bounding_sphere = {};
 	for (int i = 0; i < plugin->nr_instances; i++) {
 		struct RE_instance *inst = plugin->instances[i];
 		if (!inst || !inst->draw || !inst->make_shadow || !inst->model)
 			continue;
-		// Start with the model's AABB, inflated with shadow_volume_bone_radius.
-		vec3 inst_aabb[2];
-		glm_vec3_subs(inst->model->aabb[0], inst->shadow_volume_bone_radius, inst_aabb[0]);
-		glm_vec3_adds(inst->model->aabb[1], inst->shadow_volume_bone_radius, inst_aabb[1]);
-		// To save CPU cycles, consider only the translation components of bone transforms.
-		vec3 bone_translation_aabb[2];
-		glm_aabb_invalidate(bone_translation_aabb);
-		for (int j = 0; j < inst->model->nr_bones; j++) {
-			glm_vec3_minv(inst->bone_transforms[j][3], bone_translation_aabb[0], bone_translation_aabb[0]);
-			glm_vec3_maxv(inst->bone_transforms[j][3], bone_translation_aabb[1], bone_translation_aabb[1]);
-		}
-		if (glm_aabb_isvalid(bone_translation_aabb)) {
-			glm_vec3_add(inst_aabb[0], bone_translation_aabb[0], inst_aabb[0]);
-			glm_vec3_add(inst_aabb[1], bone_translation_aabb[1], inst_aabb[1]);
-		}
-		// Apply local transform.
-		if (inst->local_transform_needs_update)
-			RE_instance_update_local_transform(inst);
-		glm_aabb_transform(inst_aabb, inst->local_transform, inst_aabb);
-
-		glm_aabb_merge(inst_aabb, aabb, aabb);
+		if (bounding_sphere[3] > 0.0f)
+			glm_sphere_merge(inst->bounding_sphere, bounding_sphere, inst->bounding_sphere);
+		else
+			glm_vec4_copy(inst->bounding_sphere, bounding_sphere);
 	}
-	if (!glm_aabb_isvalid(aabb))
+
+	float radius = bounding_sphere[3] * 1.2f;  // Add some padding.
+	if (radius <= 0.0f)
 		return false;
 
-	// Create a orthographic frustum that contains the AABB.
-	vec3 center;
-	glm_aabb_center(aabb, center);
-	vec3 light_pos;
-	glm_vec3_scale(plugin->shadow_map_light_dir, -glm_aabb_radius(aabb), light_pos);
-	glm_vec3_add(light_pos, center, light_pos);
+	// Create a orthographic frustum that contains the bounding sphere.
 	mat4 view_matrix;
-	vec3 up = {0.0, 1.0, 0.0};
-	glm_lookat(light_pos, center, up, view_matrix);
-
+	glm_look(bounding_sphere, plugin->shadow_map_light_dir, GLM_YUP, view_matrix);
 	mat4 proj_matrix;
-	glm_aabb_transform(aabb, view_matrix, aabb);
-	glm_ortho_aabb(aabb, proj_matrix);
-
+	glm_ortho(-radius, radius, -radius, radius, -radius, radius, proj_matrix);
 	glm_mat4_mul(proj_matrix, view_matrix, dest);
 	return true;
 }
diff --git a/src/hll/ReignEngine.c b/src/hll/ReignEngine.c
index bc16071..cc52541 100644
--- a/src/hll/ReignEngine.c
+++ b/src/hll/ReignEngine.c
@@ -651,8 +651,17 @@ static bool ReignEngine_SetInstanceShadowVolumeBoneRadius(int plugin, int instan
 	return true;
 }
 
-//bool ReignEngine_GetInstanceDebugDrawShadowVolume(int plugin, int instance);
-//bool ReignEngine_SetInstanceDebugDrawShadowVolume(int plugin, int instance, bool flag);
+static bool ReignEngine_GetInstanceDebugDrawShadowVolume(int plugin, int instance)
+{
+	struct RE_instance *ri = get_instance(plugin, instance);
+	return ri && ri->shadow_volume_instance && ri->shadow_volume_instance->draw;
+}
+
+static bool ReignEngine_SetInstanceDebugDrawShadowVolume(int plugin, int instance, bool flag)
+{
+	return RE_instance_set_debug_draw_shadow_volume(get_instance(plugin, instance), flag);
+}
+
 //bool ReignEngine_SaveEffect(int plugin, int instance);
 
 static bool ReignEngine_GetEffectFrameRange(int plugin, int instance, int *begin_frame, int *end_frame)
@@ -1899,8 +1908,8 @@ HLL_LIBRARY(ReignEngine,
 	    HLL_EXPORT(SetInstanceSoftFogEdgeLength, ReignEngine_SetInstanceSoftFogEdgeLength),
 	    HLL_EXPORT(GetInstanceShadowVolumeBoneRadius, ReignEngine_GetInstanceShadowVolumeBoneRadius),
 	    HLL_EXPORT(SetInstanceShadowVolumeBoneRadius, ReignEngine_SetInstanceShadowVolumeBoneRadius),
-	    HLL_TODO_EXPORT(GetInstanceDebugDrawShadowVolume, ReignEngine_GetInstanceDebugDrawShadowVolume),
-	    HLL_TODO_EXPORT(SetInstanceDebugDrawShadowVolume, ReignEngine_SetInstanceDebugDrawShadowVolume),
+	    HLL_EXPORT(GetInstanceDebugDrawShadowVolume, ReignEngine_GetInstanceDebugDrawShadowVolume),
+	    HLL_EXPORT(SetInstanceDebugDrawShadowVolume, ReignEngine_SetInstanceDebugDrawShadowVolume),
 	    HLL_TODO_EXPORT(SaveEffect, ReignEngine_SaveEffect),
 	    HLL_EXPORT(GetEffectFrameRange, ReignEngine_GetEffectFrameRange),
 	    HLL_EXPORT(GetEffectObjectType, ReignEngine_GetEffectObjectType),